Nikola template plugin

import os

from jinja2 import Template
import yaml
from docutils.parsers.rst import Directive, directives
from nikola.plugin_categories import RestExtension

class TemplatePlugin(RestExtension):

    name = "render_template"

    def set_site(self, site):
        """Set Nikola site."""
        self.site = site
        # Even though listings don't use CodeBlock anymore, I am
        # leaving these to make the code directive work with
        # docutils < 0.9
        TemplateDirective.site = site
        directives.register_directive('template', TemplateDirective)
        Template.folders = 'data'  # site.config['DATA']
        return super().set_site(site)


class TemplateDirective(Directive):
    required_arguments = 1
    option_spec = {'name': directives.unchanged}
    has_content = True

    def run(self):
        """Run render template directive."""
        self.assert_has_content()

        data_path = os.path.join('data', self.arguments.pop(0))
        with open(data_path) as f:
            data = yaml.load(f.read())
        self.state.document.settings.record_dependencies.add(data_path)
        template = Template('\n'.join(self.content))
        self.state_machine.insert_input(template.render(data=data).splitlines(),
                                        data_path)
        return []